Hours later, the father posted on Facebook writing that Addy had died.

“This all happened so much faster than we expected, but that in itself is a blessing because she suffered so little at the end,” he wrote.

By the time Addy passed, the photo of her brother Jackson saying goodbye to her had gone viral. In an interview with The Washington Post, Sooter shared the moments before and after the photo was taken.

Sooter said that Jackson knew of his sister’s health condition, and that she may not survive. He refused to leave her side that night.

The two were playing and talking, but it was time to sleep for the night.

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Jackson tucked his sister into bed, held her hand and whispered, “I love you.”

Minutes after that, Addy’s breathing and heartbeat became irregular. Several hours went by and the little girl died just after 1 a.m. local time.